We at GitLab believe the author did not responsibly disclose this security information in a proper manner, and today we removed the list of hosts in accordance with our terms of service ( https://about.gitlab.com/terms/ ). The author says that he contacted "about 30 merchants directly", but the published list includes over 1000 merchants. Most merchants were neither informed nor given a chance to respond in a timely…
Responsible disclosure works because companies are responsive to disclosure.
Full disclosure works because companies are negligent and they've been outed.
The author did contact said websites, it is their responsibility to fix the issue in a timely manner. Removing the content was akin to a newspaper removing stories relating to certain politicians to protect them. It is censorship.